The invention is particular, but not exclusively, concerned with terminating such tubular bodies formed from filamentary or yarn materials that are braided, knitted or woven to form the tubular body. For convenience such a tubular body is referred to herein as a textile tubular body irrespective of the materials and/or construction.
It is a feature of such tubular bodies that the components thereof are movable relative to each other when the body is subjected to various forces and often the materials, such as filaments of glass fibres or plastics material which are smooth and/or exhibit shape memory, result both in a tendency for such bodies to fray at any cut ends and difficulty in capping them by traditional ferrule designs.
Such a traditional ferrule design comprises a metal cap having a tubular wall and an annular end face which is swaged against the tubular wall with the tubular body therebetween to crimp the body. A textile tubular body, particularly a thin walled one, is difficult to retain within such a simple ferrule.
It is known to terminate a tubular body, in joining fluid carrying hoses end-to-end or securing a component thereto, by having inner and outer parts which include radial projections that co-operate to crimp the tubular body. Such multi-part arrangements are usually employed with tubular bodies having a significant wall thickness which is amenable to such crimping but does not lend themselves to simple one-piece terminating ferrules.
Such an arrangement is disclosed in U.S. Pat. No. 5,015,015 which describes joining a pair of overlapping coaxial pipe segments by inserting between their respective inner and outer overlapping tubular surfaces a plurality of circumferentially short clips having radially oppositely inclined barbs which bite into and penetrate both pipe segments. The oppositely inclined barbs are also directed in opposite axial directions so that each is also inclined towards the end of the pipe wall it penetrates to preclude removal.
U.S. Pat. No. 3,911,960 describes an end piece for a tubular element such as a solid pipe, intended to be fitted thereto temporarily to avoid damage to the element surfaces at or near the ends due to handling of the element, including lifting by crane and hook. A tubular body or skirt is moulded to effect a tight encompassing fit on the end region of the tubular element and has an end face, arranged to overly the end of the element, which is divided into radially directed fingers to localise stress concentrations due to lifting by inserting a hook into the tubular element. The fingers are arranged, if necessary, to individually deflect and lie parallel to the inside wall of the tubular element under the action of a local lifting load to prevent damage by such hook. The end piece is not intended as a permanent termination and designed to be removed after use without damage to the tubular element, that is, without intruding into the surface of the tubular element in any way.
In this specification the term tubular body is intended to encompass both a body that is circumferentially continuous at manufacture and one that is circumferentially discontinuous, at least until the time of use and possibly in use, provided such body does in use assume a generally tubular shape for the purpose of defining an enclosure, albeit apertured. To this end it is known for a tubular member to be slit longitudinally such that is has longitudinally extending edges which are arranged to extend parallel to each other, either overlapping or spaced apart, to permit objects or materials to pass through the wall or to envelope such objects or materials; such longitudinally slit tubular members may be opened out and flattened for easy storage and assume a naturally tubular form or may have edge coupling means such that naturally flat material is curled into and maintained in, tubular form. It is also known for a tubular member to be defined by wrapping a flat strip helically about a core or former, with or without adjacent or overlapping edges secured to each other to define a tubular body.
It is an object of the present invention to provide a ferrule for, and a method of, terminating a tubular body, particularly a textile body, that is of simple one-piece construction and mitigates disadvantages of known arrangements. It is also an object of the present invention to provide a method of terminating and/or joining ends of a multi-layer tubular body.
The invention employs piercing of the tubular body and to this end is suited only for use with the above mentioned textile tubular body which has interstices between filamentary components or a cast or extruded tubular body of thermoplastics or other material whose walls are readily pierced, and within this specification the term "pierceable tubular body" is used in relation to such a body of manufactured or assembled tubular form having a structure that enables it to be pierced.
According to a first aspect of the present invention a ferrule or cuff for a pierceable tubular body (as herein defined) comprises a circumferentially continuous or discontinuous longitudinally extending substantially tubular wall, dimensioned to receive a said tubular body, and an annular end wall comprising a plurality of fingers arrayed about the end of the tubular wall and extending radially inwardly from an associated section thereof, each finger carrying a barb member inclined at an acute angle with respect to the finger and longitudinal axis and directed towards the associated section of the tubular wall, said end wall being swageable in use causing each said finger to lie parallel to its associated section of the tubular wall to enclose a portion of said tubular body therebetween and cause the barb member to penetrate the body and point generally in the direction of the end of the tubular body.
According to a second aspect of the present invention a method of terminating a pierceable tubular body (as herein defined) comprises assembling a ferrule as claimed in the preceding paragraph onto the end of the body with the body received in the tubular wall of the ferrule, swaging the end wall of the ferrule causing the fingers to bear against the inside of the body alongside the tubular wall and causing the barb member carried by each finger to pierce the body and upon penetration therethrough be deflected by the tubular wall to lie substantially parallel to the tubular wall and the finger and pointing towards the end of the body.
According to a third aspect of the present invention a method of terminating and/or joining multiple, coaxially disposed layers of a pierceable tubular body (as herein defined) comprises assembling a ferrule as defined in the last but one paragraph, and whose barb members are longer than the total wall thickness of the bodies, onto the end of the outer body such that all bodies are received adjacent the tubular wall of the ferrule, swaging the end wall of the ferrule causing the fingers to lie against the inside of the inner body alongside the tubular wall and causing the barb member carried by each finger to pierce the bodies and be deflected by the tubular wall to point toward the end of the outer body.
Embodiments of the invention will now be described by way of example with reference to the accompanying drawings.